Machine for making an electrode assembly



July 3, 1951 P. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY 6Sheets-Sheet 1 Filed Oct. 12, 1949 KOFOZ on NA...

mm wv mm R. w S. on o: 8. m E E n on M R M f Ow G 09 O V O B. N T I|| I-i I L Y m E F u u mm u. m2 G m2 6 a E 8 f 8 N C M 5 o: S R No P v. w B 35 8 N 6 k 2 o! aw 5:; V 52; fl EH23 565:6 195 8 L l 33 52% m. 3 31 n 6Sheets-Sheet 2 INV EN TOR.

llvll PRICE LREED P. L. REED Ii 010? b0 0 MACHINE FOR MAKING ANELECTRODE ASSEMBLY July 3, 1951 Filed Oct. 12, 1949 ATTORNEYS.

y 1951 P. L. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY 6Sheets-Sheet 3 Filed Oct. 12, 1949 INVENTOR. PRICE L. REED BY AT TORNES.

July 3, 195] P. I.. REED 2,559,547

MACHINE FOR MAKING AN ELECTRODE ASSEMBLY Filed Oct. 12, 1949 sSheets-Sheet 4 I uz INVENTOR. PRICE L'. REED ATTORNE S.

y 1951 P. L. REED 2,559,547

MACHINE FOR MAKING AN ELECTRODE ASSEMBLY QA-Jwr AT T0 RN YS.

6 Sheets-Sheet 6 IN V EN TOR.

P. L. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY July 3, 1951 FiledOct. 12, 1949 n m "m "u we a an n u v um I 8 l4 Ne 81 mm 3. 3 No 8. t 83 3 3 n "u -v PRICE L. REED BY ATTORNEY Patented July 3, 1951 MACHINEFOR MAKING AN ELECTRODE ASSEMBLY Price L. Reed, Royersford, Pa.,assignor to Superior Tube Company, Philadelphia, Pa., a corporation ofPennsylvania Application October 12, 1949, Serial No. 120,911

9 Claims.

This invention relates to the manufacture of cathodes for thermionictubes and has particular reference to the disc-type of cathode which isused in various cathode ray tubes, television pickup tubes and tubes ofthe so-called lighthouse construction.

In tubes of the type just mentioned the thermionic emission is obtainedfrom a relatively small, cup-shaped disc coated with alkaline earthoxides. The disc must be rigidly mounted within the tube a fewthousandths of an inch from a grid member and in accurate parallelalignment therewith. The disc is supported by a metal tubular memberwhich may be of any conventional form, i. e., seamless or of lock seam,welded, welded and drawn, boxed, orwrap-around ribbon type, and alsoserves as a means of conducting heat to the 'disc or cup carrying theoxides to heat it to electron-emitting temperature. An insulatedtungsten, molybdenum or similar wire is usually placed within the tubeto provide sufilcient heat by electrical resistance to make possibleattainment of the proper temperature.

In order to support the cathode assembly, ceramic or similarheat-resistant insulators are employed. These insulators, generally inthe form of a flat disc, are mounted on the tubular member prior to theattachment of the cup to the tubular member. The attachment of the cupto the tubular member is generally accomplished by inserting the tubularmember into the cup which fits as a snug cap over the end of the tubeand then welding the cup to the tube.

It is an object of this invention to maintain an accurate dimensionlongitudinally between the face of the disc and the face of the cupwhile welding the cup to the tube supporting the disc.

Another object of this invention is to maintain accurate parallel planealignment between the face of the disc and the end face of the cup whilewelding the cup to the tube supporting the disc.

In my Patent N 0. 2,476,454, issued July 19, 1949, there is disclosed amachine for making the cathode assembly which welds the cap to the tubeone weld at a time and rotates the assembly to successive weldingpositions under a single welding electrode.

It is a further object of this invention to provide means forautomatically making a plurality of welds evenly spaced around theperiphery of the cap without moving the assembly until the welding iscompleted.

These and other objects of the invention will become apparent from thefollowing description, read in conjunction with the accompanyingdrawings, in which:

2 Figure 1 is a plan view of the apparatus involved;

Figure 2 is an axial section of the welding and gauging means taken onthe plane indicated by 22 in Figure 1 above the mounting plate, and anelevation of the apparatus below the mounting plate;

Figure 3 is a side elevation of the apparatus showing the controlmechanism lying below the mounting plate;

Figure 4 is a front elevation of the gauging and welding means and themechanism lying below the mounting plate;

Figure 5 is a front elevation of the welding means, as viewed frombetween the gauging means and the welding means;

Figure 6 is an enlarged fragmentary side elevation, entirely in section,showing the cathode assembly held by the gauging means in position to bewelded with two of the welding electrodes in position for welding;

Figure '7 is a diagram of the electrical circuit involved; and

Figure 8 is a side elevation of the welding and gauging means shown inthe lower portion of Figure 1.

Referring to the figures there is shown a driving motor 2 coupledthrough the shaft 3 to a speed reducer 4 which, in turn, drives theshaft 5 and the one-revolution clutch 6. The one-revolution clutch 6 maybe of any conventional type employing a solenoid controlled releaseelectrically energized through the lead wires 8 and I0. When theone-revolution clutch is energized, sprocket wheel l2 which is afiixedto the shaft ll driven by the clutch 6 will rotate for one revolutiondriving the chain 14. The chain l4 drives the sprocket wheel [6. Thesprocket wheel l6, having twice the number of teeth of the sprocketwheel l2, will be .driven one-half a revolution with each revolution ofthe sprocket wheel l2 or with each operation of the one-revolutionclutch 6. Inasmuch as the motor 2, the speed reducer 4 and theone-revolution clutch 6 may take the form of any conventional apparatusof this type, and are not essential parts of the present invention, theywill not be described in detail.

The welding apparatus shown generally at I in Figure 2 is supported bythe supporting member l8 which is mounted on the mounting plate 20.Passing through a bore in the supporting member 18 is the insulatingsleeve 22 which is held in position within the member l8 by the setscrews 24.

Mounted on the portion of the insulating sleeve 22 extending outwardlyfrom the left side of supporting member [8, as viewed in Figure 2, isthe member 2G which is held in position on the insulating sleeve bymeans of set screws 28. Rotatably mounted on the member 26 is the member39 which is retained in proper position by virtue of its bearing on theface 32 of the member 26 and its bearing on the insulating collar 34which is located between the extended flange portion 36 of the member3i! and the support I8. Rigidly mounted to the extended flange portion-35 of the member 33 is the sprocket wheel H5 which is driven as theresult of operation of the onerevolution clutch t, and causes the memberto rotate for one-half a revolution about the stationary member 26 witheach operation of the one-revolution clutch.

Mounted within the extended rim portion SI of the rotatable member 30are a pair of cam members 33 which are adapted to rotate with the member3!! and depress the electrode mounting assemblies as will be hereinafterdescribed. Mounted on the external surface of the rotatable rim iii arefour buttons or projections 35.

Slidably mounted within the radially disposed slots 23?, within thestationary member 26, are the electrode mounting blocks 38. Each of theblocks 33 is slidably retained within the slots 3'! by the two retainingplates 39 which are afiixed to the stationary member 26 by screws 4|.The electrode mounting blocks are urged in radially outward positions bythe spring 23 acting between the extended portion 25 of the block 38 andthe inner end of the radially extending slots 2| in the stationarymember 25.

The machine, as described herein, contains four electrodes and fourelectrode mounting assemblies. It will be obvious, however, that anynumber of pairs of electrodes and electrode mounting assemblies may beused within the limitations imposed by the space limitations and the proportionate sizes of the parts involved. The following description of theelectrode, and electrode mounting assemblies, is directed to oneassembly only, it being understood that all of the assemblies are alike.

Mounted on the electrode supporting block 38 by means of the screws 49is the electrode mounting yoke 42. The mounting yoke 42 is insulatedfrom the support block 33 by means of a sheet of insulating material 44lying between the yoke 42 and the block 313 and the insulating sleeves46 surrounding each of the mounting screws M Contained within borespassing through the extended ends of the mounting yoke 42 is theelectrode sleeve 43 to which is affixed a collar 50. Mounted over theelectrode sleeve 43 is a spring 52. The inner end of the spring bearsagainst a collar 59 and the outer end bears against the inside of theouter extended portion of the yoke 42. Mounted within the electrodesleeve 48 is the electrode holder 54, in the inner end of which isinserted the electrode tip 56.

Clamped to the inner ends of the electrode holders are the conductorlead mounting blocks 59, Connected to the blocks 5% and [ii are theflexible lead wires 64 and 65, joining the blocks as and El to thewelding cable 66, and connected to the blocks 62 and 63 are the flexiblelead wires 6i and 68 joining the blocks 62 and B3 to the welding cable69. The welding cables 66 and 69 are connected to a conventional typewelding current timer H! which receives power from power lines I53 andI55.

Each of the conductor lead mounting blocks 69, 6!, 62 and 63 serves theadditional purpose, when clamped against its associated electrode sleeveby the action of its associated clamping as viewed in Figure 2.

screw 59, of compressing the sleeve against its associated electrodeholder 54, thus firmly retaining the electrode holder 54 in itspreestablished position within the sleeve 48. The outer end of theelectrode holder is threaded and a nut 58 is provided to facilitate thesetting of the position of the electrode holder within the electrodesleeve. For example, the electrode holder 54 is placed within theelectrode sleeve 48 in a posttion inwardly further than will berequired. Then the clamping screw 59 is partially tightened and themounting block will hold the electrode holder in position within thesleeve, and then, by tightening the nut 58, the electrode holder may bedrawn outwardly through the sleeve to exactly the desired position,after which the clamping screw 59 is tightened completely.

Mounted within the insulating sleeve 22 in the support member I8 is thesleeve member H which is held in position in the sleeve 22 by set screws'52. The member ll contains a central bore 13 which is threaded at itsright hand end The partially threaded sleeve member 14 is inserted intothe bore '13 and may be adjustably positioned within the member H bymeans of the screw threads and locked into position by the lock nut '75.ber 14 contains a partially threaded central bore within which ismounted the partially threaded rod 16 which may be adjustably positionedby means of the screw threads and locked in that position within themember '14 by the lock nut '13. The rod 16 has a portion of reduceddiameter 19 extending for approximately half its length from the lefthand end, as viewed in Figure 2.

Mounted within the enlarged central bore 11 at the left hand of thesleeve member H, as viewed in Figure 6, is the solid cylindrical member80. The member is held in position on rod 16 by means of the set screw82. The member 80 is positioned to bear against the spacer member 84which, in turn, bears against the end of the sleeve member 14. Mountedin each of three bores 36 uniformly spaced within the member 80 is aplunger member 88 which is urged outwardly by the spring member 96acting between the plunger rod collar 92 and the plug member 94 in themember 80.

It will be observed that the position of the member 80 may belongitudinally adjusted by turning the sleeve member 14 within themember H, and that the relation between the left hand end of the rodmember 16 and the left hand end of the member 80 may also be adjusted bypositioning the rod member 16 within the sleeve member 14.

Also mounted on the base plate 20 is the member 96, containing the gibslot 97, within which is slidably mounted the gib member 98, supportingthe member 99 on which is mounted the gauge plate I00 and the micrometerassembly, generally indicated at IUI.

The gauge plate IUD, which is fixedly mounted to the member 99, has onits upper portion four projections I02 separated by the central boreI03. The end faces I94 of these projections are accurately machinedfaces lying on a common plane perpendicular to the surface of the bedplate 20 and normal to the longitudinal axes of the rod 16. Themicrometer assembly includes the fixed member I 05, mounted on themember 99, and containing the threaded central bore I06 within which ismounted the adjustable micrometer stem [01. Attached to the micrometerstem i0! is the conventional micrometer rotatable outer member I08carrying the usual micrometer scale The sleeve mem' markings. Thus, byadjusting the micrometer, the longitudinal distance between the end IIIof the micrometer shaft and the end faces I04 of the gauge plateextension can be accurately adjusted.

Also attached to the base plate 20 is the bracket I42, mounting thelimit switch I44 and the limit switch actuating lever I46. Mounted onthe lever I46 is the projection I48 which is positioned so as to bedepressed by the projections 35 on the rotatable member 30 when themember 30 is rotated. Upon depression, the lever I46 actuates the limitswitch I44 closing the circuit therethrough and initiating the operationof the welding timer I and causing welding current to flow, as will behereinafter described.

Mounted below the base plate 20 is the mechanism for actuating themicrometer and the gauge plate mounting gib 98. This mechanism includesthe member II2 which is adapted to be extended downwardly and providedwith a foot pedal, or other suitable means not shown, which may beactuated by an operator. The member II 2 has the flattened upper endportion II3 which is pivotally mounted by means of the pin II4 to asupporting bracket H5. The supporting bracket II 5 is attached to theunderside of the base plate 20. Aifixed to the flattened portion II3 ofthe member H2 is the pin II 6 which is engaged by the slot H7 in one endof the lever member H8. The lever member H8 is pivotally mounted on themounting bracket I I 5 by means of pin I I9.

The other end of the lever member IIB has an extended portion I whichcontains the bore I2I through which is passed rod member I22. The rodmember I22 is held in engagement with the lever member extension I20 bymeans of the rod collar I23 and the spring I24. The tension of thespring I24 may be adjusted by setting the locking pair of lock nuts I26in any desired position on the threaded end of the rod I22.

Mounted on the other end of the rod I22 is the tongue I28. The tongueI28 is coupled to the clevis I30 by a pin I32. The clevis I30 is mountedon the rod member I34 which is rigidly afllxed to the sliding gib 98.

Also mounted on the underside of the mounting plate 20 is the bracketmember I36. Aflixed to the bracket member I36 is the block I37. The stopscrew I38 passes through a threaded bore in the block I31 and is lockedin position by the lock nut I39. Also mounted on the bracket I 36 is thelimit switch I40. Both the stop screw I38 and the limit switch I 40 areadapted to be engaged by the lever member I I8 upon operation of themechanism, as will be hereinafter described.

When it is desired to assemble a cathode assembly by welding a cap to atube and disc assembly, the operator will place a cathode cap I50 overthe proper end of a tube I52 of a cathode tube and disc assembly andplace this assembly over the end of the rod member I6, as shown inFigure 2. The tube and disc and cap assembly are more clearly shown inFigure 6 which is drawn to show the relative positions of the variousparts involved in gauging and welding the cap to the tube at the timethe welds are made.

After having placed the unwelded electrode assembly into position overthe end of the rod member I6, the operator will actuate the member H2,extending below the base plate 20, moving it to the position 2', asshown in construction lines in Figure 3. This motion of the member II2results in moving lever member I I8 into the position also shown inconstruction lines and numbered H8 whereat motion is arrested by thestop screw I38 and its end portion I20 actuates the limit switch I 40.When the lever member II 8' is in this depressed position, the lever endportion I20 will bear against the spring I24 which in turn bears againstthe lock nuts I26 drawing the rod I 22 to the right, as viewed in Figure3, to the position I22 causing the rod member I34 to assume the positionI34 and causing the end I I I of the micrometer stem and gauge faces I04to move to the right and engage the tube disc and cap assembly, as shownin Figure 6, with a force as determined by the degree of compression ofspring I24.

With the parts in this position, the end III of the micrometer shaftwill bear against the oathode assembly cap I50, holding it firmlyagainst the end face of the rod I6. The nd faces I04 of the gauge plateextensions bear against the face of the disc I54 causing it to depressthe spring loaded members 88 back into the plug 80, with the result thatthe action of the springs 00 holds the disc I54 firmly against the gaugeplate faces I04. Thus the relation between the left hand face of thedisc I54, as viewed in Figure 6, and the left hand or outer surface ofthe cap I50 is firmly established by the gauging means as to bothparallel plane alignment and longitudinal dimensional relation.

There is provided a suitable electric current timing means I5I which maybe any one of a number of conventional timers and which receives powerfrom the power lines I 53 and I 55 and is initiated by the closure ofmicroswitch I40 to pass current through leads 8 and I0 to the solenoidcontrol coil 9 of the one-revolution clutch 6. The timer I5I is adjustedto energize the coil 9 for a sufiicient period to permit theone-revolution clutch to commence its operation and to deenergize thecoil for a sufficient time before the completion of one revolution ofthe clutch in order to prevent a second operation of the clutch fromoccurring.

When the operator has actuated the member II 2 and the lever II 8 toengage the cathode assembly parts within the welding and gauging means,as hereinbefore described and as shown in Figure 6, further motion ofthe members H2 and H8 will not move the gauge and micrometer assemblybut will merely compress the spring I24 as shown at I24 as the lever II8moves to its extrem position where it actuates the limit switch I40 andits motion is arrested by the end of the stop screw I38.

Closing the contact of the limit switch I40 initiates the timing meansI5I actuating the onerevolution clutch. Upon operation of theonerevolution clutch, the member 30 carrying the cam members 33 will berotated for half a revolution, as previously described. As the rotatingcam members 33 engage the outer ends of an oppositely disposed pair ofwelding electrode mounting blocks 38 the mounting blocks are cammedinwardly b the bevelled portion I60 of the leading edges of the cams 33as the cams rotate in a clockwise direction, as viewed in Figure 5. Thecontinued rotation of the member 30 and the cams 33 will cause the innercam faces I62 to pass over the ends of the electrode mounting block 38holding the electrode mounting block in radially inward position duringthe period of dwell of the cam faces I 62; and further rotation willallow the mounting block 38 to move outwardly over the bevelled trailingedges IBI of the cam in response to the urging by the spring member 23.

When a cam moves a mounting. block inwardly the yoke member 42 which iscarried by the mounting block will bear against the upper portion of thespring 52'. The other end of the spring, bearing against the member 58,will carry the electrode sleeve and the electrode holder in wardly intocontact with. the cathode cap, as shown in Figure 6. After travel of theelectrode and electrode sleeve has been arrested: by contact of theelectrode tip with the cathode cap, further motion of the block 38 andthe yoke member 42' will serve only to compres the spring 52. Thisspring compression provides an electrode tip force and an electrodehaving yieldable contact with the cathode cap;

Referring to Figure 5, when the rotatable member 3I' is rotatedclockwise to a position where the cam members 33 have depressed thevertically lying electrode mounting blocks 38, the button 35, shown atthe bottom of the member 3I in Figure 5, will have rotated to a positionwhere it will actuate the microswitch Me. Upon actuating limit switchM4, welding timer l9 will be operated and welding current passed throughwelding cable 66, jumper lead 64 to the block 60 and thence through theelectrode sleeve 48, electrode holder 54 and electrode tip 55 throughthe oathode cap I50, the cathode tube I52, the rod IE, which is made ofa conductive material such as brass, through the opposite side of thecathode sleeve I52 and the opposite side of the cathode cap I50 into theelectrode tip 56, electrode holder 54, sleeve A8, block 62, jumper E8and the welding cable 69 back to the welding timer. At the points ofcontact of the two electrodes 56 to the cathode cap I50, resistancewelds will be form-ed between the cap I50 and the tube I52 in. aconventional manner. The period of dwell or the length of the inner faceI52 of the cam 33 may be selected to provide a sufficiently long timeduration of contact for the electrodes upon the oathode cap to provide asuitable welding condition. With the apparatus as described and themember 30 making a half a revolution with each operation, it will beobvious that the two pairs of welding electrodes are each depressed oncewith each operation of the one-revolution clutch. Thus, two pairs, or atotal of four welds, will be made on the cathode assembly with eachoperation of the welding apparatus.

After the one-revolution clutch has completed its cycle and the weldingtimer has interrupted the flow of welding current, the operator mayreturn the member II2 to its normal position whereupon, by the action ofrod I22, the gib 98 carries the micrometer and gauge assembly back awayfrom the cathode assembly to a position as shown in Figure 2. Theoperator may then remove the welded assembly from the machine and placeinto the machine a new assembly for weldmg.

In my copending application, Serial No. 75,577, filed February 10, 1949,there is disclosed a method and apparatus for mounting the disc I54 onthe tube I52 by forming beads in the tube on each side of the disc.

In the copending application of Thomas H. Briggs, Jr., Serial No.75,845, filed February 11, 1949, now U. S. Patent 2,551,871, granted May8, 1951, there is disclosed a method and apparatus for striking thebeads, closing the beads and causing them to bear flatly against thedisc, as shown in the present application.

It is extremely difiicult to maintain the extreme degree of accuracy ofdimension required between the face of: the cap member I50 andthe faceof the disc I 54 by relying on. providing the proper length of tubingI52 extending beyond the face of the disc. This problem is furthercomplicated by the inconsistencies occurring in the bend radius attainedin the manufacture of adrawn cap such as member I55. The presentinvention provides a means fOr assembling the cap to the tube with thehigh degree of accuracy required since neither the length of the tubenor the dimensions of the cap determine the final central spacing of theface of the insulating disc from the face of the cap.

A particularly desirable feature of the present invention is that, whenthe cap and tube and disc assembly have been positioned in the gaugingmeans and are accurately held in proper alignment, the welding operationis completed before the cap and tube and disc assembly are released bythe gauging means. Thus, once the parts have been properly positioned,all of the welding is completed before the parts are released. Thus,there is assured accurate alignment between the parts.

What is claimed is:

1. A welding apparatus adapted to be associated with a welding currenttimer and comprising at least one pair of radially disposed 0pposedwelding electrodes, individual means re"- taining each of saidelectrodes, means radially slidably mounting each of said electroderetainin means, means rotatable about the circumference of said mountingmeans for intermittently depressing said retaining means inwardly withinsaid mounting means, said electrodes moving inwardly in response to theaction of said depressing means on said retaining means and engagingopposite sides of parts to be Welded together, and means for initiating'a welding current timer to pass welding current through said electrodesand the parts when said electrodes are in engagement therewith.

2. A weldin apparatus adapted to be associated with a welding currenttimer and comprising at least one pair of radially disposed opposedwelding electrodes, individual means yieldably retaining each of saidelectrodes, means radially slidably mounting each of said electroderetaining means, means rotatable about the circumference of saidmounting means for intermittently depressing said retaining meansinwardly within said mounting means, intermittently rotating meansactuating said rotatable depressing means, said electrodes movinginwardly in response to the action of said depressing meanson saidretaining means and yieldably engaging opposite sides of parts to bewelded together, and

means for initiating a welding current timer to pass welding currentthrough said electrodes and the parts when said electrodes are inengagement therewith.

3. A welding apparatus adapted to be associated with a welding currenttimer and comprising at least one pair of radially disposed opposedwelding electrodes, individual means yieldably retaining each of saidelectrodes, means radially slidably mounting each of said electroderetaining means, means rotatable about the circumference of saidmounting means for intermittently depressing said retaining meansinwardly within said mounting means, intermittently rotating meansactuating said rotatable depressing means. said electrodes movinginwardly in response to the action of said depressing means on saidretaining means and yieldably engaging opposite sides of parts to bewelded together, and means responsive to the position of saidintermittently rotating means for initiating a welding current timer topass welding current through said electrodes and the parts when saidelectrodes are in engagement therewith.

4. A welding apparatus adapted to be associated with a welding currenttimer and comprising a plurality of pairs of radially disposed pposedwelding electrodes, individual means retaining each of said electrodes,means radially slidably mounting each of said electrode mounting means,means rotatable about the circumference of said mounting means forintermittently depressing successive opposed pairs of said retainingmeans inwardly within said mounting means, successive pairs of saidelectrodes moving inwardly in response to the action of said depressingmeans on said retaining means and engaging opposite sides of parts to bewelded together, and means for successively initiating a welding currenttimer to pass welding current through each pair of electrodes and theparts to be Welded when said electrodes are in engagement therewith.

5. A welding apparatus adapted to be associated with a welding currenttimer and comprising a plurality of pairs of radially disposed opposedwelding electrodes, individual means retaining each of said electrodes,means radially slidably mounting each of said electrode mounting means,means rotatable about the circumference of said mounting means forintermittently depressing successive opposed pairs of said retainingmeans inwardly within said mounting means, intermittently rotating meansactuating said rotatable depressing means, successive pairs of saidelectrodes moving inwardly in response to the action of said depressingmeans on said retaining means and engaging opposite sides of parts to bewelded together, and means for successively initiating a welding currenttimer to pass welding current through each pair of electrodes and theparts to be welded when said electrodes are in engagement therewith.

6. A welding apparatus adapted to be associated with a welding currenttimer and comprising a plurality of pairs of radially disposed opposedwelding electrodes, individual means retaining each of said electrodes,means radially slidably mounting each of said electrode mounting means,means rotatable about the circumference of said mounting means forintermittently depressing successive opposed pairs of said retainingmeans inwardly within said mounting means, intermittently rotating'meansactuating said rotatable depressing means, successive pairs of saidelectrodes moving inwardly in response to the action of said depressingmeans on said retaining means and engaging opposite sides of parts to bewelded together, and means responsive to the position of saidintermittently rotating means for successively initiating a weldingcurrent timer to pass weldin current through each pair of electrodes andthe parts to be welded when said electrodes are in engagement therewith.

'7. A welding apparatus adapted to be associated with a welding currenttimer and comprising at least one pair of radially disposed opposedwelding electrodes, individual means yieldably retaining each of saidelectrodes, means radially slidably mounting each of said electroderetaining means, means rotatable about the circumference of saidmounting means including cams for intermittently depressing saidretaining means inwardly within said mounting means, intermittentlyrotating means actuating said rotatable depressing means, saidelectrodes moving inwardly in response to the action of said depressingmeans on said retaining means and yieldably engaging opposite sides ofparts to be welded together, and means for initiating a welding currenttimer to pass welding current through said electrodes and the parts whensaid electrodes are in engagement therewith.

8. A welding apparatus adapted to be associated with a welding currenttimer and comprising at least one pair of radially disposed opposedwelding electrodes, individual means yieldably retainin each of saidelectrodes, fixed means radially slidabl mounting each of said electroderetaining means, means slidably mounting each of said electroderetaining means, means rotatable about the circumference of saidmounting means for intermittently depressing said retaining meansinwardly within said mounting means, intermittently rotating meansincluding a one-revolution clutch actuating said depressing means, meanscontrollable by an operator to initiate the operation of theonerevolution clutch, said electrodes moving inwardly in response to theaction of said depressing means on said retaining means and yieldablyengagin opposite sides of parts to be welded together, and meansresponsive to the position of said depressing means for initiating awelding current timer to pass welding current through said electrodesand the parts when said electrodes are in engagement therewith.

9. A welding apparatus adapted to be associated with a welding currenttimer and comprising a plurality of pairs of radially disposed opposedwelding electrodes, individual means retaining each of said electrodes,means radially slidably mounting each of said electrode mounting means,means rotatable about the circumference of said mounting means includingcams retaining means inwardly within said mounting means, intermittentlyrotatin means actuating said rotatable depressing means, successivepairs of said electrodes moving inwardly in response to the action ofsaid depressing means on said retaining means and engaging oppositesides of parts to be welded together, and means for successivelyinitiating a. welding current timer to pass welding current through eachpair of electrodes and the parts to be welded when said electrodes arein engagement therewith.

PRICE L. REED.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,061,378 Heany May 13, 19131,122,665 Thomson Dec. 29, 1914 1,554,385 Still Sept. 22, 1925 2,079,042Saives May 4, 1937 2,183,219 Hollesen Dec. 12, 1939 2,372,413 WeightmanMar. 27, 1945 2,476,454 Reed July 19, 1949

